In order to improve the corrosion resistance to hot gases of metal components, such as turbine blades, it is known to vapor deposit or electrodeposit onto the components a metallic interlayer prior to application on the component of an aluminum diffusion coating.
The electrodeposition of an interlayer has disadvantages which are inherent in the process. For example, the thickness of the interlayer can not be maintained within small tolerances and accordingly uniform, thickness of the interlayers can not be achieved.
Interlayers produced by sputtering (cathodic disintegration) have the disadvantages of producing microscopic defects and internal compressive stresses in the interlayers which impede an undisturbed subsequent application of the aluminum diffusion coating and when the coated component is subjected to thermal and/or oxidic stresses, pore formation is developed at the interface between the metallic interlayer and the aluminum diffusion coating.